Photoperiodism in Relation to Hormones as Factors in Floral Initiation and Development

  title={Photoperiodism in Relation to Hormones as Factors in Floral Initiation and Development},
  author={Karl C. Hamner and James A. Bonner},
  journal={Botanical Gazette},
  pages={388 - 431}
1. A description is given of a simple method whereby one portion of a plant may be subjected to one photoperiod while another portion of the same plant is being subjected to another photoperiod. 2. Floral initiation in Xanthium pennsylvanicum results if plants are subjected to photoperiods shorter than 15 hours with accompanying dark periods of longer than 8 hours. If Xanthium plants are subjected continuously to photoperiods longer than 16 hours with accompanying dark periods shorter than 8… 

Photoperiodic Induction as Influenced by Environmental Factors

Xanthium plants, when grafted to vegetative plants, continue to supply a stimulus for flower initiation when exposed to continuous long photoperiod, and soybeans exposed to an induction period of three or more consecutive long dark periods would not produce new primordia subsequently unless they were again exposed to another induction period.

Photoperiodic Responses of Dill, a Very Sensitive Long Day Plant

Vegetative plants transferred from conditions of short to those of long photoperiod were induced to flower after exposure to as few as four longphotoperiods, while seedlings from the commercial dill seed employed flowered soon after germination if grown on 9-hour photoper Period.

Effect of Some Environmental Factors on Floral Initiation in Xanthium

  • L. Mann
  • Biology
    Botanical Gazette
  • 1940
Data is given showing the influence of the number of photoinductive cycles to which plants are exposed on the rate of development of flower structures and the photoperiod following a long dark period has a pronounced effect on the initiation and development of flowers.

Photoperiodic Responses of Several Varieties of Soybeans

The initiation of flower primordia in many varieties under continuous light shows that darkness is not a necessary condition for floral initiation in them, and the reactions causing induction are accelerated if the plants are subjected to daily periods of darkness.

Effect of Light and Temperature on Floral Initiation in Cocklebur and Biloxi Soybean

In cocklebur, the conditions brought about during the photoperiod may be diminished to such a point that plants fail to initiate floral primordia when subsequently subjected to a 12-hour dark period, and in Biloxi soybean the use of short alternating periods of darkness and light may be a more economical method of maintaining "short-day" plants in a vegetative condition.


  • J. Bonner
  • Biology, Medicine
    Plant physiology
  • 1940
Evidence is presented to show that the production of vitamin Bi, a hormone for the growth of roots, is affected by the length of day to which the plant is subjected, and this effect has a profound effect on the extent of the root system.


The discovery by GARNER and ALLARD (3) that many plants have specific photoperiodic requirements for floral initiation has led to considerable research to determine the effect of light in the

Studies on the Nature of the Endogenous Rhythm Affecting Photoperiodic Response of Biloxi Soybean

The results obtained with Biloxi soybean support those obtained by Lockhart and Hamner with Xanthium in which a second dark period following a brief exposure to light partially nullified the effect of an inductive dark period.

Translocation of the Reproductive Stimulus in Sugar Beets

  • M. Stout
  • Environmental Science
    Botanical Gazette
  • 1945
The results indicate that the biennial is not able to synthesize reproductive-inducing substances as a result of photoperiod alone, as annuals do, but also requires cool-temperature exposure.

Effect of Variation in Temperature During Photoperiodic Induction Upon Initiation of Flower Primordia in Biloxi Soybean

None of the temperature combinations used in these experiments brought about the initiation of flower primordia when photoperiods of 16 hours were used.



Correlative Effects of Environmental Factors on Photoperiodism

In I920 GARNER and ALLARD (7, 8) announced the results of experiments and observations on the responses of plants to alternating periods of light and darkness, or variations in the length of day and

Locus and Physiology of Photoperiodic Perception in Plants

In order to minimize difficulties and at the same time employ contrasted photoperiodic exposure on contiguous parts, plants were grown to a convenient height under vegetative light conditions on opposite sides of a thin, opaque panel having a long, 2-inch horizontal slit.

Eflect of the relative length of day and night and other factors of the environment on the growth and reproduction in plants

  • Jour. Agr. Res

Photoperiodism in relation to hydrogen-ion concentration of the cell sap and the carbohydrate content of the plant

  • Jour. Agr. Res

Die Wirkung von Genen, tiefen Temperaturen und bluhenden Pfropfpartnern auf die Bluhreife von Hyossyamus niger L

  • Biol. Zent

Contribution a la theorie du photoperiodisme

  • II. Compt. Rend. Acad. Sci. U.R.S.S

Localization of the response in plants to relative length of day and night

  • Jour. Agr. Res

Gesammelte Abhandlungen uber Pflanzen-physiologie. Leipzig. I:229-260. I892